RENORMALIZATION SCHEMES AND RENORMALONS

Various ways on how higher order corrections can reveal themselves if integrated over the ir region are discussed. We show that in different renormalization group (RG) schemes and for some observables one has n o factorial divergences. We argue that for treating things in the ir r egion it is preferable to start with a RG scheme without the ir Landau pole in the running coupling constant. The uncertainties for the tau lepton width resulting from accounting for higher order corrections ar e also discussed.